A content delivery system can be or include a wireless content delivery system, such as the MediaFLO™ system developed by QUALCOMM Incorporated of San Diego, Calif. The content delivery system can be or include a content delivery platform based on wired or optical connections, in addition to or instead of a wireless interface. In general, the content delivered by the content delivery system can include video media, such as video clips encoded in the Real™ format, the Motion Pictures Group (.mpg) format, the Windows Media format by Microsoft Corp., or other video codec or format. The content can include audio media, such as music tracks or broadcast recordings encoded in Motion Pictures Expert Group (MPEG)-1 Audio Layer 3 (MP3) format, Microsoft Corp. “.wav” format, RealAudio™ format, or other audio codec or format. The content can further include textual content, such as streaming stock quotes, weather reports, or other data.
In a content delivery system, data can be transmitted via a set of logical channels. In some implementations, a set of logical channels can comprise a set of multicast logical channels (MLCs) such as those employed in the aforementioned MediaFLO™ system. The use of a set of logical channels can increase the time diversity of data received within a superframe, improving reception of the data.
Advanced forward error correction techniques can also be implemented to protect the data during transmission. The MediaFLO™ system uses a concatenated coding scheme with Reed-Solomon coding for an outer code and turbo coding for an inner code. Conventional concatenated coding schemes of this type provide hard decision inputs to a Reed-Solomon erasure decoder at the receiver, where recovery of erased symbols is not attempted if the number of erasures is greater than the redundancy of the Reed-Solomon code. Iterative turbo-Reed-Solomon decoding using a Reed-Solomon soft input-soft output (SISO) decoder, as described in “Jiang,” can provide improved performance relative to the performance of the conventional concatenated coding scheme using a Reed-Solomon erasure decoder. Iterative decoding based on parity check matrix can be an efficient method for decoding some codes. However, this type of iterative decoding is suboptimal for codes associated with dense parity check matrices, such as Reed-Solomon codes. The iterative decoding performance largely depends on the particular parity check matrix used.